On one of my recent visits to the Channel Island of Jersey, where I conduct some of my fieldwork on the heritage of the German Occupation of the Second World War, I was given a private viewing of one of the island’s newest archaeological discoveries. The Jersey Hoard was found in June 2012 and was judged to be the world’s biggest Celtic coin hoard ever discovered. Jersey Heritage’s conservator, Neil Mahrer, allowed me into his laboratory so I could see how the project was coming along.

Before I moved into the field of Conflict Archaeology around seven years ago, I was an Iron Age archaeologist, and so the hoard was particularly exciting for me to see. Sticking out of the massive clump of corroded green-coloured coins was a golden torque, a form of necklace which is usually associated with Iron Age hoards found in Norfolk. The most famous hoard of torques ever found in the UK comes from Snettisham, and these are on display in the British Museum.

The Jersey hoard is estimated to contain around 70,000 coins, as well as pieces of silver and gold jewellery, and it was found and excavated in one solid mass measuring 140 x 80 x 20 cm and weighing about three quarters of a ton. The coins are made of a silver-looking alloy called billon, a mixture of silver and copper, although during the conservation process (still in its very early stages) a gold coin was found and more, I predict, can be expected. The hoard was excavated and removed from the site as a large clump, complete with a 5cm covering of soil it so it wouldn’t dry out. That clump was wrapped in layers of a clear plastic film in order both to support and contain the hoard during excavation and conservation, to prevent it from breaking into pieces.

Since the hoard was brought to his lab, where it has been kept damp to prevent it drying out, Neil Mahrer’s job has been a busy one. He recently made an epoxy resin replica of the hoard, while it was still whole, and is now waiting to hear whether he will be given funding to purchase a laser scanner so that he can make a 3D virtual digital record of the hoard as it is dismantled. I was very pleased to be asked by Neil to write a letter of support for this important purchase.

Recording the hoard digitally in this fashion is very important; research in Iron Age studies over the last 20 years has revealed that the deposition of objects often shows a patterning which was governed by ritual concerns. If this patterning can be identified, it will facilitate a greater understanding of Iron Age cosmology and ritual practices in Jersey. Although thus far Neil has been able to work out that the hoard was deposited in a number of bags or packages of some sort, it will be revealing to be able to pinpoint precisely where in the hoard certain items were placed – items such as torques and jewellery which, currently, are peeping temptingly out of the corroded block.

Meanwhile, Neil’s job is a slow one: the hoard needs to be dismantled, one coin at a time, a job which he has estimated will take six to eight years for one person. His task will then be to record, clean and chemically treat each coin in turn to remove any corrosion. His conservation blog documents the process.

Talking to Neil about the laser scanner made me mull over the changes in the way that Iron Age coins have been treated and interpreted over time. We know that these coins were minted by the Coriosolites, an Armorican people who lived around 50BC in the area of modern-day St Malo and Dinan in France, just across the water from Jersey. In the past, archaeologists might have interpreted them as having been buried by Armoricans fleeing Roman invasion, to prevent Roman soldiers or others finding them in a time of conflict and uncertainty. Alternatively, they could have been payment to Iron Age Jersey people who fought as mercenaries in the Gallic Wars, alongside their kin across the water.

Today archaeologists might be more inclined to suggest that these coins were a diplomatic gift, or perhaps a ritual gift to the gods that no one had any intention of removing. The local papers joked that perhaps Jersey was an off-shore financial centre and tax haven 2,000 years ago!

While we cannot know for sure whether any of these interpretations (or even a combination of them) is correct (although we can make an educated guess at which one is wrong!), it is important for archaeologists to make sure that their interpretations are contextual and site-specific. Further excavation at the site of the coin hoard might help in this respect. Jersey (and the Channel Islands as a whole) is also acquiring a reputation for hoards; a few months after the coins were discovered, a late Bronze Age hoard of axe heads turned up just a few miles away.